These are still used in mission critical environments where someone with a Wyse Terminal sits on one end (or at least a terminal emulator) and calls systems in places like a cable company's head end. It's definitely antiquated but, in many cases, old school tech works fine, so penny-pinching folks choose not to upgrade.

I had a hayes 2400baud and a hayes 9600 baud. Once speeds got up to 14.4k , Hayes kind of disappeared.